Dear Doctors: I wound up in the emergency room with a heart arrhythmia. It kept beating too fast, too slow and skipping beats, one after the other nonstop. They did an EKG but said it looked normal. How could that be? They also did a test for troponin, which was normal. Why was that included?
Dear Reader: An arrhythmia is as it sounds: a departure from the heart's normal steady cadence. They can be caused by structural problems within the heart or a glitch in the electrical system that controls the rate and rhythm of the heartbeats. Arrhythmias can also occur during a heart attack. When a problem with the heart arises, these possible causes inform decisions about subsequent testing.
In your case, the collection of chaotic arrhythmias raised two important questions: What does the electrical activity of your heart look like, and has there been damage to the heart muscle? The latter is the reason for the troponin test you are asking about. Troponin is a specialized protein that helps regulate muscle contraction. If heart muscle cells are damaged, as happens in a heart attack, they release troponin into the bloodstream. The normal level provided reassuring evidence that no recent or significant damage to your heart muscle had occurred.
In asking for an electrocardiogram, or EKG, your doctors were trying to capture a real-time picture of your heart's electrical activity. The instrument turns your heart's electrical signals into a series of squiggly and spiky lines. Each of those tells a story about how electrical impulses are traveling through your heart and making it beat. The challenge here is "real-time." The diagnostic recording of an EKG typically lasts about 10 seconds. If your heart does not misbehave during that brief interval, the results will appear to be normal.
The next step is often a wearable heart monitor. Rather than the brief EKG snapshot of electrical activity, wearables are designed to record the heart's rhythm over much longer periods. This increases the chance of capturing intermittent arrhythmias. One type of wearable is known as a Holter monitor. A portable device with self-stick electrodes that attach to the chest, it continuously records the heart's electrical activity, typically for 24 to 48 hours. Newer versions can record for longer periods. A so-called patch monitor is a small wireless device. It adheres directly to the chest and can track heart rhythm for days or weeks. Some monitors are also equipped with a button the wearer can push when symptoms occur, allowing doctors to zero in on the relevant data.
We are used to our hearts doing their jobs quietly, a kind of background hum that doesn't draw attention to itself. That makes a heart arrhythmia potentially quite alarming. Because your own experience included several types of abnormal heartbeats over an extended period, seeking emergency medical care was a wise decision. Your normal troponin results are reassuring. If your doctors have recommended extended monitoring and you follow through, it can help identify the source of these episodes.
(Send your questions to [email protected], or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)
